1. Technical Field
This disclosure relates to an image processing method, a program, an image forming apparatus, an image processing apparatus, and an image forming system.
2. Description of the Related Art
Ink-jet recording apparatuses are widely known as image forming apparatuses such as printers, facsimiles, copying machines, complex machines thereof, and the like, in which a droplet ejecting head is employed as a recording head. Such ink-jet recording apparatuses perform image forming (recording, character printing, image printing, and printing are used as having the same definition) by ejecting ink as recording liquids on paper from an ink recording head (paper is not limited a specific form but includes OHP, for example, where ink liquids, other liquids, and the like are capable of adhering thereto, and paper is also referred to as record media, recording media, recording paper, recording sheet, and the like).
In order to spread ink-jet recording apparatuses from a personal environment to an office environment, the following two problems must be overcome. A first one is recording speed. Except for specific-type ink-jet recording apparatuses for industrial use, general-use ink-jet recording apparatuses perform recording by repeatedly scanning paper using a recording head much smaller than the recording paper and spraying ink liquids thereon. This method can be referred to as a recording method based on “lines” and such a method is very disadvantageous in terms of recording speed in comparison with electrophotographic image forming apparatuses performing recording based on a paper (page) unit, namely, “area”.
So as to solve this disadvantage in terms of printing speed, some apparatuses improve the scanning speed by prolonging the cycle of injecting ink liquids, decrease the number of scanning by using a large size recording head or two-way recording, employs efficient scanning sequences in which scanning is controlled in the minimum length thereof by scanning only those portions for recording image data, or the like. In accordance with this, ink-jet recording apparatuses performing a small to normal amount of printing are even capable of achieving a recording speed exceeding that of electrophotographic image forming apparatuses.
A second problem is plain paper support. When dedicated paper is used, images recorded through ink-jet printing are capable of reproducing extremely high-quality images. Ink-jet recording apparatuses for personal use today are capable of obtaining such an image quality as if photographs were taken.
However, this dedicated paper is normally expensive, so that it is difficult to use such paper in companies, for example, where a strict cost management is required. Further, images output for use in the offices are not required to have such a quality. Thus, it is disadvantageous to be only capable of forming high-quality images when dedicated paper is used.
In view of this, composition of ink has been improved so as to support plain paper. For example, development of low permeation dye ink and pigment ink has been conducted and fixation adjuvant has been used, for example. Latest ink-jet recording apparatuses are capable of forming images having the same quality as that of electrophotographic image forming apparatuses even with plain paper generally used in the offices or paper generally used as copying paper.
In this manner, ink-jet recording apparatuses have become vary attractive products also for use in the offices due to improved printing speed and image quality thereof. In particular, ink-jet recording apparatuses are highly advantageous in terms of cost in comparison with laser printers and have been used as desktop printers because such ink-jet recording apparatuses have been readily downsized.
However, different from image forming apparatuses such as laser printers, offset printers, and the like in which a coloring agent is fixed on a surface of paper, ink-jet recording performing fixation using the permeation of coloring agent into paper always has problems and limitation relating to the permeation process thereof.
In other words, when plain paper support is considered, there are various types of so called “plain paper” practically available on the market, so that plain paper includes thick and thin paper, coarse and dense paper with fibers and additives, paper with additives for improving brightness, and paper classified into light coated paper in which thin coating is applied to a surface thereof, and the like. These types of “plain paper” have different permeation for a coloring agent applied to the surface thereof in each paper and thus pose a problem in that a density of recorded images may be different as a result.
In view of this, Patent Document 1 discloses a printing system for printing color images. In order to obtain desirable tone of color or gradation characteristics, the disclosed printing system outputs plural sample hues for each of basic colors, namely, R, G, B, from the printer based-on data not subjected to a color balance modification from processing of basic color setting of a printer driver. A color balance table correction process adjusts modification parameters of a color balance modification table used in a color modification process. In accordance with this, in a printing process performed after the color adjusting process, a color balance modification is performed based on tone of color determined by user preference (selection).
Patent Document 1: Japanese Laid-Open Patent Application No. 2000-190572
In addition, regarding the difference of density of recorded images, Patent Document 2 discloses a printing method. The disclosed printing method flexibly sets the amount of a printing agent used upon printing in each printing condition so as to maintain reproducibility of color of a printing result. An application outputs a printing direction of printing data. A printing information obtaining unit in a printer driver or a printer obtains various types of limitation such as types of image, printing methods, and the like, namely, colors of toner used upon printing, an intensive number, simplex/duplex printing, the number of scanning for character printing, and the like. The printing information obtaining unit transmits the obtained limitation to a data calculating unit in a usage limiting unit. In accordance with this, limitation values of usage of the printing agent in each of obtained limitation are switched.
Patent Document 2: Japanese Laid-Open Patent Application No. 2005-001275
Further, Patent Document 3 discloses another printing method. The disclosed printing method is capable of readily adjusting arrangement positions of attachment information, density of printing, and sizes, and of printing desired attachment information along with images without losing impression of printed images. The attachment information printed along with image information is selected on an image selecting screen displayed on a display unit, the image information being read by an image scanner unit. A printing position of the selected attachment information, density of printing, a printing size are selected and specified on a position selecting screen, a density specifying screen, and a size specifying screen. An attachment information processing unit attaches image information to be read in accordance with the specified printing position, density, and size. A printer unit prints the image information on a recording medium, the information being provided with the attachment information.
Patent Document 3: Japanese Laid-Open Patent Application No. 2001-016434
Further, Patent Document 4 discloses another printing method. The disclosed printing method is capable of automatically performing a color matching process in accordance with types of objects on a printer drive side. A type determining unit determines types of objects to be drawn based on an input drawing order. An attribute information replacing unit holds plural sets of attribute information of a color matching method prepares in each type of objects, selects corresponding attribute information from the plural sets of attribute information based on the determination result of the type determining unit, replaces attribute information attached to the drawing order with the selected attribute information, and outputs the drawing order and drawing color information to a color changing unit. The color changing unit performs a color matching process on the drawing color information based on the attribute information replaced by the attribute information replacing unit.
Patent Document 4: Japanese Laid-Open Patent Application No. 2004-266860
In the above-mentioned methods of adjusting the density of recorded images, γ correction or adjustment of a halftone process value is performed. However, when density is adjusted based on such γ correction or adjustment of a halftone process is performed, gradation characteristics are inverted, so that density is adjusted without maintaining gradation.